Production of thermophilic endo-ß-1,4-xylanases by Aspergillus fumigatus FBSPE-05 using agro-industrial by-products.

In the present paper, endo-ß-1,4-xylanase production by Aspergillus fumigatus was evaluated in solid-state fermentation using low-cost substrates such as sugarcane bagasse (SCB), brewer's spent grain (BSG), and wheat bran (WB). The partial characterization of the crude enzyme was also performed. In the experimental conditions, the highest levels of endo-ß-1,4-xylanase production by A. fumigatus FBSPE-05 occurred within 8 days incubation when using SCB/liquid medium at 1:2 ratio (219.5 U g(-1)) and 4 days incubation when using WB/liquid medium at 1:1 ratio (215.6 U g(-1)). Crude enzyme from this last condition was used to enzyme characterization, showing best enzyme activity at 60 °C and pH 6.0, which suggests a thermophilic endoxylanase. The crude enzyme retained 73% of its activity after 1 h at 60 °C, and zymogram has shown three bands of endo-ß-1,4-xylanase activity, with different molecular masses. A. fumigatus FBSPE-05 was able to grow and produce good levels of endo-ß-1,4-xylanase using agro-industrial by-products, making this strain worthy for further investigation. To our knowledge, this is the first study reporting the use of SCB and/or BSG as sole substrates for endoxylanase production by solid-state fermentation using A. fumigatus.

Brewer's spent grain and corn steep liquor as substrates for cellulolytic enzymes production by Streptomyces malaysiensis.

AIMS: To evaluate cellulase production by Streptomyces malaysiensis in submerged fermentation using brewer's spent grain (BSG) and wheat bran (WB) as carbon source, and corn steep liquor (CSL) as nitrogen source, as compared to yeast extract (YE), and partial characterization of the crude enzyme. METHODS AND RESULTS: Maximum cellulase production by Streptomyces malaysiensis (720 U l(-1)) occurred within 4 days incubation when using a growth medium containing BSG 0.5% (w/v) and CSL1.2% (w/v). CMCases activity showed to be stable over an acidic pH range (2.0-7.0) and in temperatures of 40-60 degrees C. Zymogram indicated three bands of CMCase activity, with different molecular masses. CONCLUSION: S. malaysiensis was able to grow and produce good levels of CMCases using solely brewer's spent grain and corn steep liquor as low-cost substrates, making this strain and these low cost by-product worthy for further investigation, and potentially feasible for biotechnological applications in different areas. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first study reporting the use of the low-cost by-products brewer's spent grain and corn steep liquor, as sole substrates for microbial enzyme production.

Aspergillus fumigatus thermophilic and acidophilic endoglucanases.

This study evaluated the production of cellulolytic enzymes by an Aspergillus fumigatus strain, isolated from sugar cane bagasse, according to its ability to grow on microcrystalline cellulose as the sole carbon source. The effect of the carbon source (brewer's spent grain, sugarcane bagasse, and wheat bran) and of the nitrogen source (corn steep liquor and sodium nitrate) on cellulase production was studied using submerged and solid state cultivations at 30 degrees C. The highest levels of endoglucanase (CMCase) corresponded to 365 U L(-1) and was obtained using sugarcane bagasse (1%) and corn steep liquor (1.2%) in submerged fermentation within 6 days of cultivation. This supernatant was used to run a sodium dodecyl sulfate polyacrylamide gel electrophoresis that showed six bands with endoglucanase activity. CMCase activity was higher at 65 degrees C and pH 2.0, indicating that this microorganism produces a thermophilic and acid endoglucanase. Solid state cultivation favored FPase production, that reached 47 U g(-1) of dry substrate (wheat bran and sugarcane bagasse) within 3 days.

A low-cost fermentation medium for thermophilic protease production by Streptomyces sp. 594 using feather meal and corn steep liquor.

Protease production by Streptomyces sp. 594 was obtained after submerged fermentation (SF) and solid-state fermentation (SSF) using feather meal (FM) and corn steep liquor (CSL) as sole sources of carbon and nitrogen. Enzyme productions were 13.4 U ml(-1) in SF and 21.5 U g(-1) in SSF; these values were approximately 86% and 39% higher, respectively, than those obtained previously when yeast extract was used in place of CSL. The proteases, which belong to the serine and metalloproteinase classes, were active at high temperatures (55 degrees C to 90 degrees C) and over a wide range of pH values (5.0 to 10.0). Thus, these thermophilic proteases have shown interesting properties for industrial purposes. As far as we are concerned, this is the first contribution toward the microbial production of thermophilic proteases by a streptomycete using a low-cost medium composed of industrial poultry (FM) and corn processing by-products (CSL).

Thermophilic protease production by Streptomyces sp. 594 in submerged and solid-state fermentations using feather meal.

AIMS: Protease production by Streptomyces sp. 594 in submerged (SF) and solid-state fermentation (SSF) using feather meal, an industrial poultry residue, and partial characterization of the crude enzyme. METHODS AND RESULTS: Streptomyces sp. 594 produced proteases in SF (7.2 +/- 0.2 U ml(-1)) and SSF (15.5 +/- 0.41 U g(-1)), with pH increase in both media. Considering protease activity, values obtained in the liquid extract after SSF (6.3 +/- 0.17 U ml(-1)) were lower than those from SF. The proteases, which belong to serine and metalloproteinase classes, were active over a wide range of pH (5.0-10.0) and high temperatures (55-80 degrees C). Strain 594 was also able to degrade feather in agar and liquid media. Keratinase activity (80 U l(-1)) also confirmed the keratin degrading capacity of this streptomycete. CONCLUSIONS: Proteases produced using residues from poultry industry have shown interesting properties for industrial purposes. SIGNIFICANCE AND IMPACT OF THE STUDY: As far as we are concerned, this is the first contribution towards the production of thermophilic protease by a streptomycete in SSF using a keratinous waste.

Effect of different carbon sources on endochitinase production by Colletotrichum gloeosporioides.

The present work analyzes the production of endochitinase by Colletotrichum gloeosporioides, a phytopathogenic fungus, using six different carbon sources and two pH values. For quantitative assay of endochitinase activity in solution, the synthetic substrate 4-methylumbelliferyl-beta-D-N,N',N"-triacetylchitotrioside was used. The major productions were obtained at pH 7.0 and 9.0, when colloidal chitin and glucose were used, whereas xylose and lactose were not good carbon sources. When testing different concentrations of colloidal chitin, glucose and glucosamine, colloidal chitin 0.5% was the best substrate, giving values of 2.4 U at the fifth day. When using glucose, best production occurred at 0.3% concentration, after 5 days growth, with values of 1.31 U. Endochitinase production was markedly decreased in high levels of glucose and in all glucosamine concentrations tested. SDS-PAGE co-polymerized with glycol-chitin analysis showed three major activity bands of 200, 100, and 95 kDa, when incubated at 50 degrees C.

Streptomyces drozdowiczii sp. nov., a novel cellulolytic streptomycete from soil in Brazil.

An actinomycete strain, isolated from a Mata Atlântica soil sample, showing cellulolytic activity was subjected to polyphasic taxonomic characterization to determine its identity. Strain M7aT presented morphological and chemotaxonomic characteristics consistent with its assignment to the genus Streptomyces. Phylogenetic analysis of its 16S rDNA sequence revealed that the strain differed from described streptomycetes available in the public databases; the most closely related species was Streptomyces laceyi, with 98.4% nucleotide similarity. It also differed from other cellulolytic strains in its phenotypic characteristics. It is therefore proposed that strain M7aT, a cellulolytic strain with biotechnological potential, represents a novel species, named Streptomyces drozdowiczii sp. nov. The type strain is M7aT (=CBMAI 0498T=CIP 107837T=NRRL B-24297T).

Protein synthesis inhibitory activity in culture filtrates from new strains of Streptomyces isolated from Brazilian tropical soils.

AIMS: To investigate the effect of the culture supernatants from three newly isolated Streptomyces strains, 221, 235 and 606 on eukaryotic cells. METHODS AND RESULTS: Cell lines were treated with the culture filtrates and assayed for protein synthesis by metabolic labelling, followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis. RNA synthesis was investigated by [5-3H]uridine incorporation. The three culture filtrates presented a strong inhibitory activity, reducing total protein synthesis of different eukaryotic cell lines by more than 85%. No effect on cellular RNA synthesis was detected. The culture filtrates did not affect the growth of the prokaryotic cells tested. CONCLUSIONS: These new Streptomyces strains, recently isolated from Brazilian tropical soils, produce molecule(s) with inhibitory activity specific to eukaryote protein synthesis. SIGNIFICANCE AND IMPACT OF THE STUDY: Streptomyces strains 221, 235 and 606, probably representing new species, might produce new bioactive compound(s), and can be used as valuable tools to study the protein synthesis pathway in eukaryotes.

Purification and characterization of an endochitinase produced by Colletotrichum gloeosporioides.

The phytopathogenic fungus Colletotrichum gloeosporioides was analyzed for chitinase activity, the best production occurring at the fourth day. A 43 kDa endochitinase with specific activity of 413 U microg(-1) protein was purified corresponding to a 75% yield. The optima of temperature and pH for the enzyme were 50 degrees C and pH 7.0, respectively. The enzyme showed a high stability at 50 degrees C and pH 7.0. Values of pH from 5.0 up to 7.0 gave, at least, 50% of maximum activity, suggesting a biotechnological application. Further studies are in progress to determine the possible use of this endochitinase in biological control.